Version control:

• Version control is a system that records changes to a file or set of files over time so that you can recall specific versions later.
• History of all changes (who, what, when).
• Helps to avoid mistakes (working on the wrong version, deleting, …).
• Merging changes of multiple collaborators in one file.

• Git is a essentially a program on your computer, you have to communicate with it.
• GitHub (or GitLab) is a Git repository hosting service.

• A lot! Which is why I can only mention part of its functionality here.
• Working on one product in (large) teams.
• Working on things that can break.
• git can only integrate and show changes in text files.
• binary files (images, etc.) can be tracked and uploaded but changes cannot be shown.

• Git does not have a user interface.
• You can either use the terminal, or install an additional interface.
• Github has its own GUI. Some people like it.
• We will use Rstudio (and the terminal) as user interface.

Tools ➤ Global Options ➤ Git/SVN.

Make sure the first box is ticked and “git.exe” (Windows) “usr/bin/git” (MacOS) is included in the first box.

• Open the Terminal in R Studio.
• Set an email address and user name for git.

• Open the Terminal in R Studio.
• Set an email address and user name for git.

git config --global user.email "myemail@email.com"
git config --global user.name "My commit name"

• In the R console

## set your user name and email:
usethis::use_git_config(user.name = "My commit name", user.email = "myemail@email.com")

• In the R console

usethis::create_github_token() 

credentials::set_github_pat("YourPAT")

File ➤ New Project ➤ Version Control ➤ Git

• Initializes a local git repository with an R project (opening a clean R Studio session when opening).
• You can see the README file from github.
• Adds a .gitignore file.

• Specifies intentionally untracked files to ignore.
• Each line in a gitignore file specifies a pattern.
• R Studio pre-specifies some useful patterns.
• For R Markdown: Cache files! .tiff, .eps, .rdb, .rdx
• Pro tip: ?usethis::git_vaccinate()

• Tell other people (and yourself in a year) why your project is useful, what they can do with your project, and how they can use it.
• On github default README files are Markdown files!

git add .gitignore myfirstrepo.Rproj

• git can do auto-complete for file names!
• Note that many user interfaces combine git add and git commit (next step).

git add .gitignore myfirstrepo.Rproj
git commit -am "My first commit"

Commits always have a commit message.

git add .gitignore myfirstrepo.Rproj
git commit -am "My first commit"
git push

Congrats! You have done it! Now local and remote repositories are up to date!

Before you start working on the project the next time (either in terminal or within R Studio):

git pull

Pull, work some more, repeat.

git diff

First things first: You cannot break things.

Read the output!

• Resolve the conflict (Choose which changes to keep).
• Commit, and Push.

• The master branch is deployable: It contains the final product code.
• This is not where people work.
• Instead you use branches for development and then merge the code into the master branch once you are done.

I don’t really have time to get into this

• Here is the best tutorial I could find on branches: https://thenewstack.io/dont-mess-with-the-master-working-with-branches-in-git-and-github/.
• For working in a professional environment: A tutorial on pull requests: https://www.atlassian.com/git/tutorials/making-a-pull-request

• Add, commit, push, pull.
• Use it!
• git documentation and error tracking are great!

• Let’s make breakout rooms
• Then complete the in-class assignment.

Additional info (in the material folder):

Vuorre, M., & Curley, J. P. (2018). Curating Research Assets: A Tutorial on the Git Version Control System. Advances in Methods and Practices in Psychological Science, 1(2), 219–236.